System for providing traffic information

ABSTRACT

A system for providing traffic information to a plurality of mobile users connected to a network. The system comprises a plurality of traffic monitors, each comprising at least a traffic detector and a transmitter, the traffic detector generating a signal in response to vehicular traffic and the transmitter transmitting the signal. A receiver receives the signals from the traffic monitors. A computer system is connected to the receiver and is further connected to the network. The computer system in response to a request signal received from one of the users transmits in response thereto information representative of the signals transmitted by the traffic monitoring units. Alternative systems for gathering traffic information are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/891,248, filed Aug. 8, 2007, which is a continuation of U.S. patentapplication Ser. No. 11/168,046, filed Jun. 28, 2005, which is acontinuation of U.S. patent application Ser. No. 10/367,162, filed Feb.13, 2003, now U.S. Pat. No. 6,785,606, which is a continuation of U.S.patent application Ser. No. 10/218,850, filed Aug. 14, 2002, now U.S.Pat. No. 6,574,548, which is a continuation of U.S. patent applicationSer. No. 09/550,476, filed Apr. 14, 2000, now U.S. Pat. No. 6,466,862,which claims the benefit of U.S. Provisional App. No. 60/189,913, filedMar. 16, 2000, U.S. Provisional App. No. 60/166,868, filed Nov. 22,1999, and U.S. Provisional App. No. 60/130,399, filed Apr. 19, 1999.

BACKGROUND OF THE INVENTION

The present invention relates to a system for providing trafficinformation, and more particularly a system for providing trafficinformation to a plurality of mobile users connected to a network.

Commuters have a need for information relating to the congestion andtraffic which they may encounter on a commute over a road, a highway, ora freeway. Unfortunately, the prior art methods of providing trafficinformation to commuters do not allow commuters to evaluate the extentto which there is congestion on a highway on which the commuter may wishto travel.

One known method of providing traffic information consists of radioreports. A radio station may broadcast traffic reports, such as from ahelicopter that monitors traffic conditions over portions of a freeway.Unfortunately, these reports are usually intermittent in nature.Accordingly, to hear the report, the commuter must be listening to theradio station at the time the report is being broadcast on the radio.Further, the extent of the information provided is severely limited tobroad generalizations. For example, the information provided during thebroadcast may be limited to the area being currently viewed by thereporter, or the information may be based on a previous view at a priortime of another portion of the freeway. Some broadcasts may includemultiple observers of different portions of the freeway, yet thesesystems also provide incomplete information relating to overall trafficpatterns. In addition, the information provided is vague, subjective,and usually limited to broad generalities relating to traffic flow.

Another known traffic information system is provided by televisionbroadcasts. In these systems, television stations may mount videocameras pointed at certain portions of a freeway, or may broadcast videoimages from a helicopter. The television station may periodicallybroadcast traffic reports and include in the traffic report a view ofdifferent portions of the freeway from the video cameras. Again, thissystem provides little useful information to a commuter. The commutermust be watching the broadcast at the time the information is beingtransmitted. However, by the time the commuter actually gets into hisvehicle and enters a potentially congested area, the traffic may havechanged. Further, the information provided is limited to those areaswhere the traffic is being monitored and may consist of staleinformation. Often the video image is limited to a small portion of theroad, and shows traffic flowing in a single direction.

Yet another method to provide traffic information is to provide awebsite that is accessible using the Internet that contains trafficinformation. While these types of systems have the advantage ofproviding more up to date information, these systems typically provide amap for a large area. Thus, for a person commuting in a car, the systemdisplays traffic information for many areas not of interest to thecommuter. In addition, these types of systems require manipulation bythe commuter to find the relevant traffic information. For example,while the map may allow the commuter to zoom in on a particular area,the user must provide inputs to the system to instruct the system tozoom in on a particular area. However, a commuter who is activelydriving cannot operate a computer and drive at the same time. Inaddition, these systems may rely on manual entry of data received fromsubjective traffic reports and/or traffic sensors. Thus this method mayadditionally suffer from added cost due to manual labor, incorrect entryof data, and slow response to quickly changing traffic conditions.

Fan et al., U.S. Pat. No. 5,959,577, disclose a system for processingposition and travel related information through a data processingstation on a data network. In particular, Fan et al. teach the use of aGPS receiver to obtain a measured position fix of a mobile unit. Themeasured position fix is reported to the data processing station whichassociates the reported position with a map of the area. Typically, themeasured position of the mobile unit is marked and identified by amarker on the map. The area map is then stored in the data processingstation and made available for access by authorized monitor units ormobile units. An authorized monitor unit may request a specific areamap. This permits shipping companies to monitor the location of theirfleet and permits the mobile units to identify their current location inrelation to a map, which is particularly suited for the application ofnavigation to a particular destination. In addition, Fan et al. teachthat the measured position data transmitted from the mobile units may beused to calculate the speeds at which the vehicles travel. Thecollective speed data from the mobile units is then available for use bythe monitor units, such as those at the shipping company, to route thevehicles away from traffic congestions and diversions. In this manner,the dispatcher at the shipping company, to which Fan et al. teaches thedata is available to, may use the collective speed data to decide whichvehicles to contact in order to reroute them.

Westerlage et al., U.S. Pat. Nos. 5,097,377 and 5,987,377, disclose asystem for determining an expected time of arrival of a vehicle equippedwith a mobile unit.

Zijderhand, U.S. Pat. No. 5,402,117, discloses a method of collectingtraffic information to determine an origin-destination matrice withoutinfringing upon the privacy of the users.

Mandhyan et al., U.S. Pat. No. 5,539,645, is related to monitoringmovement of traffic along predetermined routes, where individual movingelements can move with a high degree of discretion as to speed exceptwhen congestion, accident or the like limit speeds. Mandhyan et al. usesthe deployment of calibrant vehicles for collecting and reportinginformation which describes vehicle speeds actually being experiencedalong the routes of interest where the data are processed statisticallyas a function of the time of day. The output provides baseline dataagainst which observations at a particular time, category, weather,event, and location can be compared, to identify the existence ofabnormal conditions, and to quantify the abnormality. To determineabnormal conditions, Mandhyan et al. teach the use of probe vehicles, Inparticular, Mandhyan et al. is applicable to monitoring the flow ofmotor vehicles along roads which are subject to delays of sufficientfrequency and severity that correction action or dissemination ofinformation announcing a delay are economically desirable.Unfortunately, the use of probe vehicles may be expensive and therelevancy of the data is limited to the availability of the probevehicles.

Lappenbusch et al., U.S. Pat. No. 5,982,298, disclose a trafficinformation system having servers that makes traffic data, images, andvideo clips available to a user interface on client devices. Lappenbuschet al. envision that the client devices are personal or desktopcomputers, network computers, set-top boxes, or intelligent televisions.The user interface includes a road map showing a plurality of roadsegments that a user can interactively select. Vehicular speedinformation is provided to the system from traffic sensors monitoringthe traffic. In addition, the user interface has a road image area thatchanges as the user selects different road segments to show recentimages of a currently selected road segment. Unfortunately, the systemtaught by Lappenbusch et al. is complicated to operate and requiressignificant user interaction to provide relevant data, which is suitablefor such “stationary” traditional computing devices.

Smith, Jr. et al., U.S. Pat. No. 5,774,827, disclose a system toalleviate the need for sophisticated route guidance systems, where thecommuter has a positioning system as well as a map database in a car. Acentral facility receives and stores current traffic information forpreselected commuter routes from various current traffic informationsources, such as local police authorities, toll-way authorities,spotters, or sensors deployed on the road ways to detect traffic flow.To achieve the elimination of sophisticated route guidance systems aportable device receives a travel time only for preselected commuterroutes from the central facility. In this manner, Smith, Jr. et al.teach that each user receives only the traffic information that isrelevant to the user's preselected commuter routes. If desired, thepreselected commuter routes may be presented as a set of route segments,where each of the segments is coded to indicate commute time. Inresponse, the user may choose an alternative route known by him that isdifferent from any preselected commuter routes. Smith, Jr. et al.further suggest that a GPS enabled portable unit for transmitting apresent position of the portable device to the central facility suchthat the central facility uses each present position to calculate atleast a portion of the current travel information. By matching multiplepositions of the portable device with known positions on the preselectedroute and measuring the time between two consecutive matched positionsthe central facility can obtain up-to-the minute traffic information tobe used in broadcasting future travel times to other users ofpreselected commuter routes. Unfortunately, the system taught by Smith,Jr. et al. requires the user to define a set of preselected commuterroutes for each route to be traveled, which may be difficult if the useris unfamiliar with the area. In addition, Smith, Jr. et al. teach thatthe user should select alternative routes that are known to the user,presumably if the commute time of the preselected commuter routes aretoo long, which is difficult if the user is not already familiar withthe area.

Pietzsch et al., U.S. Pat. No. 5,673,039, disclose a system for dynamicmonitoring of the total traffic in a stretch of road equipped withmonitoring and information-provision system, as well as warnings todrivers, and hence the possibility of regulating the traffic. The systemdoes not require that the vehicles be equipped with appropriate sensorsand transmitting equipment.

Akutsu et al., U.S. Pat. No. 5,987,374, disclose a vehicle travelingguidance system that includes data providing devices laid on a road anda vehicle. The vehicle includes a data transmitter for sending a dataproviding device traveling data of the vehicle when the vehicle passesover the vicinity of the data providing device and a data receiver forreceiving data sent from the data providing device. The traveling datamay include vehicle pass time or vehicle pass time and speed. The dataproviding devices laid on the road include a receiver for receiving thetraveling data from the vehicle and a transmitter for sending otherpassing vehicles the traveling data. A control center communicatingthrough the data providing devices laid on the road can use the receivedtraffic data from the vehicles to predict the occurrence of trafficcongestion based on the pass time and speed of a vehicle. It is assumedthat at a certain point,. vehicles were traveling smoothly at a certaintime and the speed of each vehicle has decreased drastically at the nexttime. In this case it is expected that traffic congestion will occur inthe vicinity of that point. Therefore, smooth travel can be achieved by,for example, communicating to each vehicle data etc. indicating bypassesin order not to worsen traffic congestion. Therefore, a vehicle operatorcan gain knowledge of the traveling state of a vehicle which has alreadypassed over that point and adjust travel considering traffic flow.

While all of the above systems provide some degree of trafficinformation for a commuter, nevertheless the above systems do notprovide an efficient method of collecting and presenting objectivetraffic information to a commuter. What is desired, therefore, is asystem for providing traffic information which allows a commuter toobtain information at any time desired by the commuter, that providesinformation relating to a plurality of points along a road, thatprovides information relating to different traffic levels, that providesinformation that is particularly relevant to the commuter, and thatprovides the information in an easily understood format that may beeasily utilized by a commuter while driving.

BRIEF SUMMARY OF THE INVENTION

The present invention overcomes the limitations of the prior art byproviding a system for providing traffic information to a plurality ofusers connected to a network. In a first aspect the present inventionprovides a system comprised of a plurality of traffic monitors, eachcomprising at least a traffic detector and a transmitter, the trafficdetector generating a signal in response to vehicular traffic and thetransmitter transmitting the signal. The system also includes a receiverthat receives the signals from the traffic monitors. A computer systemis connected to the receiver and is also connected to the network. Thecomputer system, in response to a request signal received from one ofthe users, transmits in response thereto information representative ofthe signals transmitted by the traffic monitors.

In a second separate aspect of the invention, a system provides trafficinformation to a plurality of users connected to a network. Traffic isdetected at each of a plurality of locations along a road and a signalis generated at each of the locations representative of the traffic ateach of the locations. Each of the signals is transmitted from each ofthe plurality of locations to a receiver. These signals are sent fromthe receiver to a computer system. The computer system receives arequest from one of the users for traffic information. In response tothe request, the computer system transmits information representative ofthe traffic at each of the plurality of locations to the user.

In a third separate aspect of the invention, a system provides trafficinformation to a plurality of users connected to a network. The systemcomprises a plurality of mobile user stations, each mobile user stationbeing associated with the display, a global positioning system receiverand a communicating device to allow each of the mobile user stations tosend and receive signals. A computer system is interconnected withanother communicating device in the network. The computer system iscapable of sending and receiving signals to the mobile user stationsusing the other communicating device in the network. The computer systemmaintains a map database and a traffic information database. The trafficinformation database contains information representative of traffic dataat a plurality of locations. At least one of the mobile user stationsprovides a request to the computer system for information together withthe respective geographic location of the mobile user station. Inresponse to the request, the computer system provides to the mobile userstation information representative of selected portions of the mapdatabase and selected portions of the traffic information database basedon the respective geographic location of the requesting mobile userstation. The mobile user station then displays graphically on thedisplay information representative of selected portions of the mapdatabase and selected portions of the traffic information database.

The traffic information database may be derived from informationobtained from stationary traffic monitors, mobile user stations, or acombination thereof. The mobile user station allows traffic informationto be displayed in a variety of manners. The display can also showgraphically the location of the car on the display. The user may selectamong different modes for displaying traffic information on the display.

The various aspects of the present invention have one or more of thefollowing advantages. The present invention allows a commuter to obtaintraffic information at any time, without waiting for a report to bebroadcast. The present invention also allows detailed informationrelating to traffic conditions based on measurements of the traffic,such as the average vehicular speed or traffic density, to be suppliedfor a plurality of locations along a road. The invention also allows theconvenient display of information in a readily understood form to theuser, such as a graphical display. The foregoing and other features andadvantages of the invention will be more readily understood uponconsideration of the following detailed description of the invention,taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a schematic of an exemplary embodiment of a system forproviding traffic information.

FIG. 2 shows a front elevational view of an exemplary traffic monitor.

FIG. 3 shows an exemplary display for a user station.

FIG. 4 shows a schematic view of an exemplary embodiment of a mobileuser unit of the present invention.

FIG. 5 is a partial electrical schematic for a traffic monitor of FIG.2.

FIG. 6 is an alternative exemplary display.

FIG. 7 shows a schematic view of another exemplary embodiment of aseries of traffic monitors along a road.

FIG. 8 shows another exemplary display for a user station.

FIG. 9 is a flow chart for a method of processing video data to yieldtraffic information.

FIG. 10 is a flow chart for an alternative method of processing videodata to yield traffic information.

FIG. 11 is a schematic representation of a road system having trafficsensors and vehicles at different locations along the road.

FIG. 12 is a combined map and traffic information databaserepresentative of the road system depicted in FIG. 11.

FIG. 13 is an exemplary embodiment of a centered display.

FIG. 14 is an exemplary embodiment of an offset display.

FIG. 15 is an exemplary embodiment of a look ahead display.

FIG. 16 is a schematic diagram of a mobile user station havingalternative mechanisms for inputting commands to the user station.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring now to the figures, wherein like numerals refer to likeelements, FIG. 1 shows a schematic diagram of the system 10 forproviding traffic information to a plurality of user stations 52connected to a network 50. A plurality of traffic monitors 20 arearranged at spaced apart locations along a road 12. The traffic monitors20 measure traffic information by detecting the speed (velocity) orfrequency of vehicles traveling along the road (freeway or highway) 12.For example, in one embodiment, the traffic monitors 20 may detect thespeed of individual vehicles 14 traveling along the road 12.Alternatively, the traffic monitors 20 may measure the frequency withwhich the individual vehicles 14 pass specified points along the road12.

FIG. 2 shows a front elevational view of an exemplary embodiment of atraffic monitor 20. The traffic monitor 20 has a detector 22 formeasuring or otherwise sensing traffic. FIG. 2 shows two differentembodiments 22A and 22B of a detector 22. The detector 22 may be anytype of measuring device which is capable of measuring or otherwisesensing traffic and generating a signal representative of or capable ofbeing used to determine the traffic conditions. For example, thedetector 22 could measure the average speed of the vehicles (cars ortrucks) 14 at locations along the road 12, or it could measure theindividual speed (velocities) of each vehicle 14. The detector 22 maydetect vehicle frequency, that is, the frequency at which vehicles passa certain point, or may measure traffic flow, consisting of the numberof vehicles passing a certain point for a unit of time (e.g., vehiclesper second). The detector 22 may use any suitable technique to measuretraffic conditions (data). For example, in one embodiment, the detector22A could employ radio waves, light waves (optical or infrared),microwaves, sound waves, analog signals, digital signals, dopplershifts, or any other type of system to measure traffic conditions(data). In one embodiment, the detector 22A uses a transmitted beam tomeasure the velocity of the vehicles 14 passing along the road 12, suchas with a commercial radar gun or speed detector commonly used bypolice. Alternatively, the detector 22A may detect when cars havingmagnetic tags or markers pass. The detector 22A may either detectsignals reflected from the vehicle or signals transmitted by thevehicles.

The traffic monitor 20 is shown with an alternative embodiment 22Bconsisting of one or more pressure sensitive detectors which extendsacross the road 12. Preferably two spaced apart detectors are positionedat a predetermined spacing to make the velocity determination readilyavailable. The pressure sensitive detector 22B detects when a vehiclepasses over the detector 22B. Such a pressure sensitive detector may beused alone or in combination with detector 22A to measure the frequencyor speed (velocity) of the traffic passing along the road 12. Likewise,the detector 22A may be used alone or in combination with the detector22B to measure the frequency or speed (velocity) of the traffic passingalong the road 12. Alternatively, detector 22B could be a wire loopburied in the road to measure changing magnetic fields as vehicles passover the loop.

The detector 22 may measure traffic conditions in a single lane of afreeway or road, or may measure average traffic information acrossseveral lanes. The detector 22 could also be embedded in each lane of aroad or freeway, such as with a pressure sensitive detector 22B.Alternatively, individual detectors could be embedded in a roadway whichwould sense signals or conditions generated by passing vehicles. Forexample, each vehicle could include a magnet or could include asignaling device which would be detected by the detector, which could bean electromagnetic sensor or a signal receiver.

Referring to FIG. 5, the traffic monitors 20 may also include aprocessor and a memory for collecting, processing, and storing trafficinformation provided by the detector 22.

The traffic monitor 20 preferably further includes a transmitter 26 fortransmitting the traffic information collected by the detector 22. Thetransmitter 26 may be any type of device capable of transmitting orotherwise providing data in either digital or analog form, eitherthrough the air or through a conductor. For example, the transmittercould be a digital or analog cellular transmitter, a radio transmitter,a microwave transmitter, or a transmitter connected to a wire, such as acoaxial cable or a telephone line. The transmitter 26 is shown astransmitting the signals through the air to a receiver 30.Alternatively, the transmitter 26 could transmit the data to anintermediate receiver before being transmitted to the receiver 30. Forexample, several traffic monitors 20 could transmit traffic informationin a daisy chain manner from one end of a road 12 to the last trafficmonitor 20 at the other end of the road before being transmitted toreceiver 30. To facilitate this type of transmission most trafficmonitors 20 would require a receiver. Alternatively, one or more trafficmonitors 20 could transmit data to other traffic monitors 20, which inturn transmit the data to the receiver 30. In order to conserve power,the transmitter 26 and the detectors 22 preferably transmit and senseinformation periodically rather than continuously. Further, the trafficinformation generated by the detector 22 is preferably averaged, orotherwise statistically modified, over a period of time so as to limitthe amount of data that needs to be transmitted and increase itsaccuracy.

In one embodiment, the traffic monitoring unit 20 may further include avideo camera 29. The video camera 29 is also connected to thetransmitter 26, so that the transmitter 26 may transmit signalscorresponding to the image sensed by the video camera 29. Alternatively,the traffic monitors 20 may be replaced by video cameras 29. Multipleimages may be obtained by a video camera and the speed of the vehicles14 determined based on image analysis of multiple frames from the videocamera(s).

One preferred type of monitor 20 utilizes signals from a digital videocamera to provide the traffic information. Traffic-related informationmay be obtained by analyzing the video sequences from the monitoringvideo cameras 29. The information may include how fast the traffic movesand how congested the road is. The speed of the traffic may be derivedby measuring the speed of vehicles in the video. The degree ofcongestion may be estimated by counting the number of vehicles in thevideo. This invention provides two algorithms for estimating trafficspeed and road congestion based on video input.

The first algorithm is based on optical flow and its flow diagram isshown in FIG. 9. First, the algorithm performs camera calibration basedon the input video of the road and the physical measurements of certainmarkings on the road. Then the algorithm (1) takes a number of framesfrom the input video; (2) computes optical flow; (3) estimates cameramotion which may be caused by wind, etc., (4) estimates independentvehicle motion after compensating the camera motion; (5) estimatestraffic speed based on the averaged vehicle motion and the cameraparameters obtained from the camera calibration step; estimates roadcongestion by counting the number of independent motion components; and(6) outputs the estimated speed and congestion results.

The second algorithm is based on motion blob tracking and its bockdiagram is shown in FIG. 10. First, the algorithm performs cameracalibration based on the input video of the road and the physicalmeasurements of certain markings on the road. The algorithm (1) takes anumber of frames from the input video; (2) estimates camera motion; (3)detects independent motion blobs after compensating the camera motion;(4) tracks motion blobs; (5) estimates traffic speed based on theaveraged blob motion and the camera parameters obtained from the cameracalibration step; estimates road congestion by counting the number ofindependent motion blobs; and (6) outputs the estimated speed andcongestion results.

Traffic monitor 20 further includes a power supply 24. The power supply24 is preferably a battery, or may alternatively be a power line, suchas a 12 or 120 volt power line. The traffic monitor 20 is shown with anoptional solar power supply 28. The power supply 24 or 28 provides thepower necessary for the detectors 22A and/or 22B, the transmitter 26,and any other electronics, such as a computer system and/or videocamera.

The receiver 30 receives the signals from the traffic monitors 20 and/orvideo cameras 29. The receiver 30 may be any device capable of receivinginformation (data) such as in either an analog or a digital form. Forexample, the receiver 30 may be a digital or analog cellular receiver, astandard phone, a radio receiver, an antenna, or a data port capable ofreceiving analog or digital information, such as that transmittedpursuant to a data protocol.

The receiver 30 receives the information from the traffic monitors 20and/or video cameras 29 and passes that information to a computer system40. The computer system 40 preferably includes a processor (such as ageneral purpose processor, ASIC, DSP, etc.), a clock, a power supply,and a memory. The computer system 40 preferably has a port 42, or anytype of interconnection, to interconnect the computer system 40 with thenetwork 50. Preferably, the computer system 40 includes informationrepresentative of the road 12 along which the traffic monitors 20 arelocated, such as a map database. The computer system 40 receives thetraffic information transmitted by the respective traffic monitors 20.The information transmitted by the traffic monitors 20 includes thelocation or identification of each particular traffic monitor 20together with the data representative of the traffic data provided bythe detector 22 and/or video camera 29 at each traffic monitor 20. Thecomputer system 40 may manipulate the traffic information in somemanner, as necessary, so as to provide average speeds or otherstatistical data. In the event of video, the computer system 40 mayprocess the images to determine the speed of vehicles. Also, the videomay be provided. Alternatively, the user stations may process thetraffic information.

In one embodiment, both the receiver 26 of the traffic monitors and thetransmitter 30 of computer system are each capable of receiving andtransmitting data. This allows for two way communication between themonitor 20 and the computer system 40. Thus, the computer system 40could remotely operate the traffic monitor 20 to change settings,diagnose problems, and otherwise provide input to traffic monitor 20 tofacilitate collection of traffic data. For example, the video camera 29could be remotely positioned to view a traffic lane of interest.

Traffic information may be provided to users in any suitable manner,such as the examples that follow. A user station 52 is connected to thenetwork 50. Preferably, the user station 52 includes a graphic displayunit 54 (see FIG. 3). For example, the user station 52 may be a standardpersonal computer with a display monitor 54. The network 50 ispreferably the Internet. However, the network 50 could also be a localarea network or any other type of closed or open network, or could alsobe the telephone network. The user station 52 sends a signal over thenetwork 50 to the computer system 40 requesting traffic information. Inresponse to receiving a request from the user station 52, the computersystem 40 transmits traffic information representative of the trafficinformation collected by the various traffic monitors 20 to therequesting user station 52. The computer system 40 may transmit averagespeeds detected by each of the traffic monitors 20 at each of theirrespective locations. The traffic information may be presented to theuser as a web page. The computer system may send traffic informationcorresponding to only some of the traffic monitors. The user may selectwhich portions of the road 12 are of interest, and the computer system40 may transmit traffic information corresponding to that portion of theroad 12.

FIG. 3 shows an exemplary display 54 displaying the traffic informationprovided by the computer system 40. The computer system 40 provides datafrom its memory which is representative of the road 12, such as datafrom a map database, which is displayed as a road 112 on the display 54.The computer system 40 also provides traffic information collected byeach, or a selected set, of the respective traffic monitors 20 which isdisplayed in portions 114 a-114 d and/or the traffic information derivedfrom individual mobile user stations having a global positioning systemlocator as described in detail below. In the exemplary display shown inFIG. 3, the portions 114 a-114 d display different colors or patternsrepresentative of average vehicle speeds (for example, in miles perhour) along different portions of the road 112. Of course, the displaymay display other types of information, such as traffic flow (vehiclesper second) or vehicle frequency. The display 54 may include informationin either graphical or text format to indicate the portion of the roaddisplayed, such as location of milepost markers or place names 116.

While the display 54 shows one format for displaying the information,other formats for presenting the information may likewise be used, asdesired. It is not necessary to provide a graphical representation ofthe road 12. Instead, information could be provided in a textual manner,such as, for example, mile post locations for each of the trafficmonitors 20 and presenting textual traffic information for eachlocation.

Thus, the system may operate as follows. The traffic monitors 20 detector otherwise sense traffic to provide traffic information. The trafficmonitors 20 may detect or otherwise calculate vehicle speed, averagevehicle speed, traffic flow, vehicle frequency, or other datarepresentative of the traffic. The traffic monitors 20 may sample eithercontinuously, or may sample at intervals to conserve power. Thetransmitter 26 transmits the signals provided by the traffic monitors 20to the receiver 30 either continuously or at intervals. Such signals maybe either transmitted directly to the receiver 30, or may be transmittedthrough other traffic monitors 20. The receiver 30 receives the signalsreceived by the various traffic monitors 20 and passes these signals tothe computer system 40. The computer system 40 receives the data fromthe traffic monitors 20. The computer system may calculate or processthe traffic information for the users, as necessary. It is not necessaryfor the traffic monitors 20 to calculate traffic data, if desired. Inresponse to a request from a user station 52, the computer system 40provides the traffic information over the network 50 to the user station52.

The system 10 has many advantages. It allows a user to receivecontemporaneous traffic information from a plurality of locations. Itallows the user to obtain immediate information rather than waiting forthe broadcast of information at specified times. Further, the amount ofinformation provided by the system is far superior to that provided byany other traffic reporting system. A user can obtain immediate andcontemporaneous traffic conditions, such as average vehicular speed,traffic flow, or vehicle frequency, for a plurality of locations along aroad. Where traffic monitors are provided along several different roads,a commuter may then select among the various alternative routes,depending on the traffic conditions for each road. The system also doesnot rely on the manual input of information, and thus providesinformation more accurately and more quickly. It also eliminatessubjective descriptions of traffic information by providing measureddata representative of traffic conditions.

In one embodiment, the computer system 40 also receives the signalsgenerated by the video cameras 29 at the respective traffic monitors 20.FIG. 3 shows an exemplary display 54 in which a video image 129 isprovided. In this embodiment, the user may select from which trafficmonitoring unit 20 the video image 129 is to be received from. Forexample, a user could initially select to view the image generated bythe video camera at a first location, and then later view the imagetransmitted by another video camera 29, preferably at another trafficmonitor 20, at a different location.

The system 10 preferably further includes the ability to send messagesabout road conditions. FIG. 3 shows such an exemplary message 130 intext format. The computer system 40 is capable of storing data messagesand transmitting the data messages with the traffic information. Thedata messages would indicate items of particular interest to thecommuter. For example, the text message 130 could indicate that therewas an accident at a particular location or milepost, that constructionwas occurring at another location or milepost, or that highwayconditions were particularly severe and that alternative routes shouldbe selected. The system 10 could provide multiple messages through whichthe user could scroll so as to receive different messages in addition tothe traffic information received from the various traffic monitors 20.In another embodiment, the user station 52 includes a voice synthesizercapable of reading the messages to the user.

In yet another embodiment, the system 10 may also provide additionalgraphical information relating to traffic conditions. For example, thecomputer system 40 could transmit the location of an accident orconstruction site along the road 12. The information would be displayedon display 54 as an icon or other symbol at the location indicating thepresence of an accident or highway construction. Such an icon is shownat 140 in FIG. 3. Alternatively, the computer system could also displayan icon representative of a restaurant, gas station, hospital, restarea, or roadside attraction. In such a system, the computer systemwould contain or be linked to a database containing such information.The information could be displayed automatically, or in response to arequest for such information from a user.

In another exemplary embodiment, the computer system 40 automaticallygenerates traffic reports to be sent to the user station 52 atpredetermined times. For example, a user may indicate that it wishes toreceive a traffic report every morning at 7:30 a.m. The computer system40 automatically sends to the user station 52 at the predetermined time(7:30 a.m., for example) the traffic information collected from thetraffic monitoring units 20. The information could be sent to bedisplayed, such as in FIG. 3, or could be sent alternatively in a textor graphical format via e-mail. The traffic report may also be providedin a format specific to the user's geographic region and/or user'sdriving habits, such as anticipated (potential) route to be traveled.The computer system 40 may also automatically send the trafficinformation to a display in the user's vehicle in response to someevent, such as turning on the vehicle, time, key press, etc.

In another embodiment, the computer system 40 allows a user to calculatethe amount of time necessary to travel from one location to anotherlocation along the road 12. The user sends a request to the computersystem 40 indicating the two locations along the road along which travelis desired. The user may, for example, indicate on the display byhighlighting the two locations on the road 112 using a computer mouse.Alternatively, the two locations may include the user's currentlocation, as determined by a vehicle based GPS system, so that only thedestination needs to be entered. The computer system 40 then calculatesthe anticipated amount of time it will take to travel from one point tothe other point based upon the traffic data collected by the varioustraffic monitors 20 between the two locations. In addition, the systemmay calculate alternative routes in order to determine the fastest routein view of the traffic information. The computer system 40 then sends asignal back to the user station 52 to indicate the amount of time thatthe travel from the first to the second location will take. The routedetermined as the best may be overlaid on a map to assist the user intravel.

In yet another embodiment of the invention, FIG. 7 shows a dividedfreeway with vehicle traffic flowing in opposite directions in each ofthe divided sections. Each section of the freeway 12 has multiple lanes12A-12C. The traffic monitors 20 measure traffic in each of the lanes12A-12C of each section 12 of the divided freeway. The monitors 20 maymeasure traffic on only one portion of the divided freeway, or maymeasure traffic conditions in each of the lanes of each of the sectionsof the divided freeway. The monitor used to measure traffic in multiplelanes may be a digital video camera.

FIG. 8 shows yet another embodiment of a display 54, which displaystraffic information for each individual lane of the divided freewayshown in FIG. 7. For example, in display 54, the traffic conditions ineach individual lane 112A-112C is displayed for the road section 112. Bydisplaying conditions for each particular lane, the system has theadvantage of allowing the user to anticipate particular lane problemswhich may occur ahead, such as a wreck 140 in lane 112C. In addition, inan alternative embodiment, the display 54 is capable of displaying theindividual location of each individual vehicle on the road 112.

FIG. 4 shows an alternative embodiment of a user station 52. Userstation 52 is a mobile unit in a car 60. User station 52 hastransmitting and/or receiving units 64 for communicating with thenetwork 50. Such transmitting and receiving units 64 may be any devicescapable of transmitting digital or analog data, such as, for example, adigital or analog cellular phone. The user station 52 may also becontained within a car 60 that further includes an associated globalpositioning system (GPS) receiver 62. The GPS receiver 62 receivessignals from GPS satellites 70 which enable the GPS receiver todetermine its location. When a commuter requests traffic informationusing the mobile user station 52, the request for traffic informationmay include the location of the user as determined by the GPS receiver62. When the computer system 40 receives this request, it providestraffic information back to the mobile user station 52 based on thelocation of the car 60 as provided by the GPS receiver 62.Alternatively, the computer system 40 may provide traffic information tothe user station 52 which in combination with the position determined bythe GPS receiver 62 displays suitable data to the user on a display oraudibly. The user station may also be a cellular phone with anintegrated or associated GPS.

FIG. 6 shows a representative display of the traffic informationprovided by the computer system 40. The information provided isessentially the same as that shown in FIG. 3, except that the display 54contains at 161 the position of the car 60. The mobile user station 52provides a significant advantage in that it allows the commuter toimmediately determine traffic information in the commuter's immediatevicinity based on the commuter's present location. The commuter does nothave to wait for a periodic traffic report. Further, traffic conditionsare provided at a plurality of locations, and the information iscontemporaneous. Based on the receipt of such information, the commutermay decide to use an alternate route rather than continue on the currentfreeway.

Thus, in the embodiment shown in FIG. 4, the system provides therelevant traffic information to the commuter or user on a timely basis.The display may be tailored to provide the information for the currentlocation of the commuter, together with the upcoming traffic that liesahead.

In a preferred embodiment, the system obtains traffic information fromusers that have a GPS receiver 62. In this system, whenever a userstation 52 requests traffic information from the computer system 40, thecomputer system 40 associates a velocity (speed) of that particular userwith its current location. The velocity may be determined through avariety of methods. In one system, when the user requests trafficinformation, the user station 52 supplies not only its location but alsoits current velocity. The user station 52 may obtain its currentvelocity in any fashion. For example, the user station 52 may track itslocation over time using the GPS receiver 62, and also keep track of thetime associated with each location by using an internal clock. Thevelocity could then be calculated by simply dividing the differencebetween respective locations by respective times. Alternatively, theuser station 52 may be connected to the vehicle's speedometer orodometer, and measure velocity using information provided by the vehicle60 itself. Alternatively, the computer system 40 itself could calculatethe velocity of each user. In such a system, each user station 52 wouldprovide the computer system 40 with a unique identification codetogether with its location. The computer system 40 then associates atime using an internal clock with each location reported by each user.Preferably, the GPS location is sent together with the current time atthe user station so that delays incurred in transmission do not changethe result. The velocity of each user could then be calculated bycalculating the difference in location for a particular user (identifiedby its unique identification code) by the respective times associatedwith each of these locations.

Thus, the computer system 40 develops a database consisting of thelocation of a plurality of users together with the respective velocitiesof each of the users. The computer system 40 thus has trafficinformation consisting at least of the velocity of the traffic for aplurality of locations corresponding to the locations for each of thereporting users. It is preferred in such a system that each user station52 would contribute to the database, but the computer system could usedata from fewer than all of the user stations 52 either requestinginformation or operating. The system may thus use the informationreceived from the user stations 52 either to calibrate the trafficinformation provided by monitors 20, or to supplement the trafficinformation provided by the traffic monitors 20. Alternatively, wherethe number of users is sufficiently large, the traffic monitors 20 mayno longer be necessary, because the users themselves through mobile userstations 52 and GPS receivers 62 provide enough traffic information togenerate useful displays of traffic information. Thus, the system mayprovide traffic information without the use of monitors 20 at all,relying solely on information derived from the mobile user stations 52.With a large number of users at a plurality of different locations, thecomputer system 40 would develop a database having a large number ofvelocities associated with a large number of geographic locations.Ideally, if every commuter on a road had a user station 52 with a GPSreceiver 62, the computer system 40 would provide not only velocity databut also traffic density or traffic frequency data. Even without everyvehicle having a user station 52 providing data to the computer system40, traffic density or traffic frequency could be calculated usingstatistical techniques that correlate the reporting user stations 52with known traffic patterns.

Thus, the combination of the mobile user station 52, GPS receiver andtransmitting and receiving units 64 provides an especially advantageousmethod for collecting traffic information. Surprisingly, this system iscapable of providing traffic information that is superior to thatcollected by stationary sensors. This is because traffic information maybe potentially collected at more locations based on the number of mobileuser stations 52, and because individual vehicle speed can be monitoredrather than average vehicle speed. In addition, the system has asignificant cost advantage in that it is not necessary to installtraffic monitors 20, or at least the number of traffic monitors 20 thatare necessary can be substantially reduced. The system also providesautomatic traffic reporting, and thus does not rely on the manual inputof data. Furthermore, the system is low maintenance, since there are notraffic monitors 20 to maintain. The system is also particularly robust,in that if a particular mobile user station 52 malfunctions, trafficinformation can still be collected for all locations based on datareported by other mobile users. In contrast, if a stationary sensor 20fails, no data can be collected from that location. Thus, the collectionof traffic data from a plurality of mobile user stations 52. to create atraffic information database provides surprising advantages and asuperior system for providing traffic information.

In the system described above using mobile user stations 52 in vehicles,the user station may initiate contact with the computer system 40 byinitiating a telephone call to the computer system 40. Alternatively,the computer system 40 could initiate a call to the user station 52,such as over the Internet using a web browser. The user station 52 wouldrespond with an appropriate signal if information was requested. Theuser station 52 could also, even if no information was desired, provideits current location (preferably with current time), and optionally itsvelocity as well, to allow the computer system 40 to gather additionaltraffic information. This would be useful in the case of vehicle basedInternet browsing for other purposes so that the traffic informationwould be updated for that user and others. In yet another alternative,the user station 52 would initiate the request to the computer system40, indicating that traffic information was desired. The computer system40 would then respond at a series of timed intervals for a set length oftime, for example, providing updates every two minutes for thirtyminutes.

In yet another alternative embodiment of the system 10, the mobile userstation 52 is a cellular telephone. The computer system 40 includes avoice synthesizer. A user may telephone the computer system 40 over acellular telephone network. In response to a request for highwayconditions, the computer system 40 generates a traffic report andtransmits the information using the voice synthesizer so that thetraffic information may be heard and understood over the commuter'scellular telephone. The location of the user may be determined by anassociated GPS receiver, or alternatively by triangulating the locationof the user by measuring the distance between the user and severaldifferent transmission receiving towers in different cells.

In yet another embodiment of the present invention the computer system40 or user station 52 may calculate the best route, such as the fastest,between a starting point and a destination based on the current trafficconditions. This functionality may further be provided in the mobileuser station 52 in the car 60 so that the driver may calculate the bestroute to accommodate for changing traffic conditions. This also assiststhe driver in unfamiliar cities where he may be unfamiliar withanticipated traffic patterns. The functionality of providing currenttraffic conditions and/or best route calculations may be overlaid onmaps available for GPS systems, household computers, and mobile userstations.

In addition, an early warning system may be incorporated into thecomputer system, user station, or mobile user station to provide warningof impending traffic jams, such as the result of a traffic accident. Forexample, if the average vehicle speed on a portion of a road ahead of adriver is less than a preselected velocity, such as 25 mph, the computersystem 40 may send a warning signal to the mobile user station 52.Alternatively, a velocity less than a preselected percentage or othermeasure of the anticipated velocity for the particular road may be usedas the warning basis. It is also envisioned within the scope of theinvention that data communications may be accomplished using radiobroadcasts, preferably encoded in some manner.

Preferably, the computer system 40 and/or the mobile user station 52 ina vehicle 60 has stored in its associated memory a map databaserepresentative of the road or highway network that contains longitudeand latitude information associated with various geographic locations onthe map. This allows easy integration of traffic data that hasassociated longitude and latitude information. For example, along aparticular section of a highway, the map database contains the latitudeand longitude of selected locations of the highway. The latitude andlongitude of the various traffic sensors 20 may be predetermined. Whendata representative of the traffic at a particular sensor 20 isreceived, the computer system 40 can easily display the trafficinformation for that particular location on the map by associating thegeographic location of the sensor 20 with the longitude and latitudeinformation contained in the map database. Similarly, where trafficinformation is derived from individual mobile user stations 52 invehicles 60 which report latitude and longitude derived from the mobileGPS receivers 62, the computer system 40 can easily associate thetraffic information received from the mobile user station 52 with themap database based on the user's reported latitude and longitude. Thus,by utilizing a map database that contains latitude and longitudeinformation for various locations, the system can easily overlay trafficinformation on top of the displayed map data by associating thegeographic data (latitude and longitude) corresponding to the trafficinformation with the geographic data corresponding to the map.

FIGS. 11 to 12 illustrate such a system. FIG. 11 shows schematically asection of a road having various locations 201-218. Along the road arepositioned various sensors 20 a-20 d whose geographic locations havebeen determined. Traveling along the road are a variety of users 401-404having respective user stations and GPS receivers. FIG. 12 illustratesone embodiment of a map and traffic information database that may bedeveloped to provide traffic information over the network to individualusers. Each of the various locations (or road segments) 201-218 has anassociated longitude and latitude. In addition, the database mayoptionally contain the associated road, as well as optionally thedirection that traffic moves at that location (for example, using a 360degree compass, 0 degrees would represent straight north while 90degrees would represent straight east). The database also includestraffic information, such as the average vehicle velocity calculated forthat location. Thus, for example, referring to FIG. 11, the trafficmonitor 20 a may be used to provide the vehicle velocity for location202. User 401 may be used to provide the vehicle velocity at location210.

Of course, while a database has been illustrated that combines both mapand traffic information, the system could use two or more databasescontaining portions of the information, such as a separate map databaseand a separate traffic information database. An example of a mapdatabase useful with such a system is Etak Map® from SONY®. The mapdatabase could reside on either or both the computer system 40 or themobile user station 52.

When a user requests traffic information from the computer system 40,the computer system 40 transmits the requested data based on either thegeographic location of the user, or for the geographic locationrequested by the user. The computer system 40 either sends the rawtraffic data requested by the user, or sends a signal representative ofthe map and/or traffic database which may be used by the user station 52to represent the map and traffic information on the display 54.

The advantage of using a map database that contains longitude andlatitude information associated with various locations on a map is thatthe system allows easy and automatic integration of traffic information,either to a database or for display. Thus, traffic information may becollected from an individual user who provides the longitude andlatitude for that user based on information derived from the user's GPSreceiver 62. The computer system then matches the location of the userto the map database based on the received longitude and latitudeinformation. The computer system 40 can then overlay the trafficinformation data received from the user onto the map database based uponthe provided longitude and latitude information. Thus, the system allowstraffic information to be updated for a map database, even though theroutes of the individual users are not predetermined. In other words, itis not necessary to know the particular route of an individual user inorder to collect useful traffic information and to update a trafficinformation database.

The traffic information database may be configured to provide trafficinformation to optimize the analysis of traffic information both bylocation and time. The spacing of the locations for which trafficinformation is associated may be either every half-mile, mile, etc. Thespacing depends on the locations of ground based traffic monitors andthe number of cars traveling through a particular spacing. If, forexample, there are traffic monitors spaced every half-mile, then thetraffic information database may report traffic information for each ofthose locations. However, for a section of road that does not havetraffic monitors, the spacing of the locations associating trafficinformation depends on the frequency of vehicles passing along thehighway and which are reporting traffic conditions. For example, wherethe traffic density is high, there will be a large number of vehiclesfrom which to gather data, and accordingly the spacing between locationsmay be small, such as ¼ mile. However, where the traffic density is low,there may be few vehicles from which to gather data, and thus thespacing may be large, such as 3 miles. The traffic information databasemay be configured so that the spacing is optimized based on the abilityto collect data for different areas. Thus, for a section of freeway in acongested area, the spacing of locations for traffic information may beshort, such as ¼ mile, while in outlying areas the spacing may be large,such as every three miles.

Similarly, the amount of time over which data is collected and averagedmay be varied. Ideally, the traffic information presented representstraffic conditions at that moment in time. However, it may be necessaryto collect data for a length of time in order to gather enough data toeither report any traffic information at all, or to insure that thetraffic information is truly representative of conditions at thatlocation. Where traffic density is high, the length of time over whichdata is collected and used to determine traffic conditions may be short,for example three minutes. In contrast, where traffic levels are light,data may be collected for a long period of time, such as fifteenminutes. When used to determine traffic information, the data may beaveraged over the period for which data has been collected.Alternatively, the traffic information could be weighted, so that oldertraffic information, though used, is given less weight when determiningtraffic information for a particular location.

By varying the spacing between locations for which data is associated inthe database and the length of time over which information is collected,the database may be configured to optimize the collection andpresentation of traffic information. For areas with high trafficdensity, the data may be gathered over a short period of time, and thespacing between locations may be small. For areas with low trafficdensity, the data may be gathered over long periods of time and thespacing may be large. The database may be configured as trafficconditions change, so that during periods of congestion the informationis gathered only over a short time for a particular area, while duringperiods of freely flowing traffic, the information is gathered over alonger time for the same area.

The present invention provides several alternative methods fordisplaying traffic information to a commuter using a mobile user station52. These various alternatives allow the user to customize the display54 to provide the desired information, and to minimize the amount ofoperation needed while driving. In one display embodiment, the display54 centers the location of the user on the displayed map, and isreferred to herein as the “Centered Display.” In the Centered Display,the mobile user station 52 determines the longitude and latitude of thecommuter based on information obtained from the GPS receiver 62. Themobile user station 52 then displays the position of the commuter at thecenter of the display 54 as shown in FIG. 13. The traffic informationand roadway data is then displayed around the commuter by comparing thelongitude and latitude of the user with the longitude and latitudeassociated with the various map locations contained in the map database.The individual user may preselect the scale of the map which will bedisplayed based on the user's preference. For example, the user may wishto show an area of one mile radius centered around the user, or two mileradius, or so forth. As the user drives along a road and the user'sgeographic location changes, the user station 52 and/or computer system40 adjusts the display 54 to reposition the map and traffic informationon the display 54. Thus, the map and traffic information scroll alongthe display 54 as the user moves along a road. For example, if thedisplay 54 shows map and traffic information at a scale of one inch permile and the direction north is shown at the top of the display, the mapand traffic information would scroll down one inch as the user drivesone mile north. The display 54 would continuously show the location ofthe user at the center of the display 54 even though the geographiclocation of the user changes.

A particular advantage of the Centered Display as discussed above isthat the location of the user can immediately be ascertained from aquick glance at the display 54, because the location of the user isalways at the center of the display 54. The user is not required toadjust the display 54 by inputting information to the user station 52 inorder to constantly view the surrounding traffic information, even asthe location of the user changes. Thus a commuter, by selecting theCentered Display, may view constantly updated traffic information forhis location without requiring any input from the commuter.

Alternatively, the display may be preselected to show the location ofthe user at a different location on the display 54, but that continuesto show the geographic location of the user at a single location on thedisplay 54, even as the geographic location of the user changes. This isreferred to as an “Offset Display.” This is a variation of the “CenteredDisplay,” but allows the user to adjust the display 54 to show moreinformation of interest to the user. For example, if the user istraveling north, and north is shown at the top of the display 54, theuser may choose to display his location near the bottom of the display(offset from the center) so as to display a greater amount of trafficinformation in the northern direction. Such a display is shown in FIG.14. Like the “Centered Display,” as the geographic location of the userchanges, the map and traffic information is automatically scrolled toshow the surrounding road and traffic, while maintaining the location ofthe user on the display 54. The “Offset Display” is particularly suitedfor driving along a relatively straight road, so that the user hasrelatively more upcoming traffic information displayed.

Yet another alternative display allows the user to display upcomingtraffic information for the road on which the user is traveling,referred to herein as the “Look Ahead Display.” In the Look AheadDisplay, the display 54 displays the location of the user near an edgeof the display 54 so as to maximize the amount of upcoming road andtraffic information which is displayed. In the Look Ahead Display, thecomputer system 40 and/or the user station 52 determines the directionof the user based on data received from the GPS receiver 62 and comparesthat direction to the road the user is traveling on. The map and trafficinformation is then selected so as to maximize the amount of road shownahead of the driver. The user may select to either display the map andtraffic information so that the cardinal ordinates North, South, Eastand West remain fixed (for example North is always at the top of thedisplay) or the road is generally centered (for example vertically onthe display) without regard to the cardinal ordinates. For example, whenthe display maintains North at the top of the display, and the user istraveling south, the display 54 would display the location of the usernear the top of the display 54, so as to increase the amount of the roadahead of the user that is displayed. If the road then curved, so thatthe user was heading in an easterly direction, the display 54 would showthe location of the user near the left hand side of the screen so as todisplay the road ahead to the east (east appearing on the right handside of the screen). This is illustrated in FIG. 15. By constantlycomparing the direction of movement of the user, as determined from thedata received from the GPS receiver 62, with the road informationcontained in the map database, the system maximizes the amount of mapand traffic information displayed based on the location and direction oftravel of the user.

Yet another type of display is the “Stationary Display.” In this type ofdisplay, the underlying map data remains “motionless” while thedisplayed location of the user changes according to the movement of theuser. For example, initially, the user's geographic location on the mapmay be shown at the center of the screen. As the user moves along aroad, the user's location would change on the display 54, while theposition of the road relative to the screen would remain constant. (Anexample of such a display is shown in FIG. 6). If the user moved to alocation not displayed, a new map would be displayed, showing thelocation of the user on the new map screen. The Stationary Display isuseful where the map database is divided into discrete units thatroughly correspond to “pages.” The Stationary Display can show the mapdata corresponding to a particular page on the display 54. New pages canbe shown as the user's location changes. The Stationary Display may bepreferred where the user is familiar with the surrounding area. TheStationary Display may also be less disconcerting to the user, becauseonly a small portion of the screen is changing (the displayed locationof the user) as the user's geographic location changes. The StationaryDisplay may also achieve some efficiencies for the system, because thecomputer system 40 would only be required to send enough data to filldisplay 54 to show the map for the area surrounding the location of theuser and then update as necessary for new traffic information. Thus, themap database could be divided into discrete portions, each portioncontaining enough information to fill a display. In response to arequest from a mobile user station 52 providing location informationderived from the GPS receiver 62, the computer system 40 identifies thecorresponding portion of the map database to the user station 52. Theuser station 52 may manage the task of integrating the map database withthe user's location to display the geographic position of the user. Newmap data would only be sent if the user's geographic location changedenough so that a different portion of the map database corresponds tothe new location.

Yet another mode for displaying map and traffic information is todisplay a particular area of interest (referred to as the “AreaDisplay”). The Area Display displays a particular geographic area ofinterest to the commuter. The location of the commuter may or may not bedisplayed, depending on whether the commuter is located within the area.To receive an Area Display, the mobile user station 52 transmits thelocation of the area of interest, and in response, the computer system40 provides pertinent map and/or traffic information. The Area Displaymay be especially advantageous where the commuter wishes to view aparticular area of interest that may be some distance away from thecommuter.

Typically the maps may be displayed with different amounts of detail,freeways, highways, parks, arterials, side streets, etc., which may beselected by the user. The amount of road detail provided for aparticular region may be associated with the map provided and thetechnique of presentation to provide additional ease of use.

Various alternatives may be used to command the user station 52 and/orcomputer system 40 to display map and traffic information. In oneembodiment, where the network is the Internet, the system may provide asettings preference web page to the user to allow the user to select theuser's individual display settings. Thus, the user may select the scaleof the display (i.e. one inch of display equals one geographic mile);the size of the display (to accommodate different screen sizes); thefrequency at which the map and traffic information is updated; theparticular default display type (such as the “Centered Display,” “LookAhead Display,” “Stationary Display,” “Area Display,” or other type);and whether information banners are to be displayed. The ability tochoose the frequency with which traffic information may be updated maybe useful to allow the user to control the cost of providing theinformation to the user. For example, where the cost of being connectedto the network is high, the user may wish to receive only short periodicupdates (such as an update every five minutes) to reduce the expense ofreceiving data.

The user may also set the time duration for which the trafficinformation is displayed to the user. The user may choose, for example,to alternate between the traffic information web site, and another website. Thus, the computer system 40 may transmit traffic information for30 seconds, and then may transmit information such as stock quotes fromanother web site for 30 seconds.

In addition to default settings, or settings that are preset by theuser, the user station 52 may be capable of receiving input from theuser to actively change how information is displayed in response to usercommands. In one embodiment, the user station 52 includes a microphone53 and voice recognition software to allow the user station 52 torespond to the voice commands of the user. (See FIG. 16). Thus, the usermay by using verbal commands select a particular mode of display,request an update of the traffic information, or change the scale of themap. Alternatively, the user station 52 may have a keyboard to acceptinput commands via the keyboard. Alternatively, the user station mayhave only a control panel 55 having several key pads 57 which correspondto particular types of preset commands. For example, one key pad mayallow a user to request traffic information. Another key pad may allow auser to zoom in on the map (i.e. change scale to show more detail),while another key pad would cause the display to zoom out (i.e. changescale to show more area). Another key pad may select for the StationaryDisplay, while yet another may select for the Look Ahead Display. Theuser station 52 may allow the user to preset the key pads 57, such asvia a web page preferences page, so that the key pads correspond to theuser's particular preferences. The use of key pads to select the mode inwhich information is displayed has several advantages. The key padseliminate fumbling by the commuter, and thus are safer to use than akeyboard. They keypads also allow the user to quickly move betweendifferent types of modes of presentation, so that the commuter maymaximize the amount of information received.

When using data from individual mobile user stations 52 to determinetraffic information, it may be desirable to screen the data to determinewhether it will be included in the traffic information database. Onetype of screening may involve comparing the geographic location of theuser with particular features stored in the map database. For example,where the user is located at a stop sign, it may not be desirable toinclude the user's reported velocity in the database. The computersystem 40 may be programmed so that data received from users at stopsigns will not be added to the traffic database. Accordingly, when theuser reports its geographic location, the computer system 40 comparesthe geographic location of the user with the map database. When thecomputer system 40 determines that the user is located at a stop sign(or other location, as desired), the data is rejected. Thus, the vehiclespeed data transmitted by the user is screened based on the particularlocation of the user.

It may also be desirable to screen out data from users that are nottraveling along roads of interest. For example, the computer system 40may maintain a limited traffic information database that only storestraffic information for selected major roads. Thus, the trafficinformation database may contain data for fewer roads than contained inthe map database. If a user is traveling along a side street which isnot included in the traffic information database, the data received fromthe user is rejected or otherwise not used. Thus, the computer system 40compares the geographic location of the user with the geographiclocations of the roads maintained in the traffic information database.If the user reports a location that is not on a road for which trafficinformation is maintained in the traffic information database, theuser's particular traffic information is rejected.

Another type of screening that may be desired is to compare thedirection of travel of each user with the direction of travel on variousroads before adding the user's vehicle speed to the traffic informationdatabase. This may be particularly important where the resolution of theGPS receiver 62 is such that the location of the user may be confusedwith one or more roads. For example, a user may be traveling along adivided road with lanes of traffic traveling in opposite directions, butthe resolution of the GPS receiver 62 does not allow the computer system40 to determine with confidence in which lane the user's vehicle istraveling. In order to determine what portion of the traffic informationdatabase to update, the computer system 40 and/or user station 52creates a directional vector associated with the user which representsthe user's direction of travel. The directional vector is determinedbased on the movement over time by the user. For example, thedirectional vector may be represented by a number ranging from 0-359;with 0.degree. representing travel straight north, 90.degree. straighteast, etc. When information is received by the computer system 40, itcompares the directions of travel of the various roads near thegeographic location of the user with the user's directional vector. Forexample, the geographic information reported by the GPS receiver 62indicates that the user is located near a particular road that hasnorth/south lanes with traffic traveling in each direction. The user'sdirectional vector indicates that the user is traveling south. Thecomputer system 40 therefore updates the traffic information database toadd the data received from the user to the traffic information databasefor the lanes of traffic moving in the user's direction of travel. Otherinstances in which the directional vector would be useful would be wherea user is crossing a particular road, such as when traveling along anoverpass or an underpass, and the resolution of the GPS receiver is suchthat the computer system 40 is unable to determine with confidence onwhich road the user is traveling. The use of the directional vector thusprevents the computer system 40 from incorrectly updating the trafficinformation database. In addition, the altitude component of the GPSdata may be used to discriminate between users on overpasses or roadsthat are vertically offset from one another.

Yet another type of screening may be necessary where the user reports nomovement. In this instance, it may be desirable to determine whether theuser's data should be added to the database, because the user may bestopped along the side of the road while traffic is nevertheless moving.Thus, the computer system 40, when it receives data from a userindicating that the user has not moved since the last time the userreported data, may cross check the data through a variety of algorithms.For example, the computer system 40 may compare the data reported by theuser with the traffic information for that portion of the roaddetermined from data taken from sensors and/or other mobile users. Ifthe traffic information derived from other sources indicates thattraffic is moving along the road, the no movement data received from theparticular user would be rejected. Alternatively, the computer system 40may be associated with a system that allows a user to request assistancein the event of a breakdown. The computer system 40 could check to seewhether the user has reported a breakdown, and if so, reject the trafficdata.

Yet another method for filtering data is to screen data received fromparticular users and/or classes of devices which are capable offunctioning as user stations. For example, it may be desirable toexclude traffic data received from buses, because buses do not providerepresentative velocity data due to frequent stops. Thus all data frombuses could be excluded. Alternatively, data from particular types ofuser stations could be excluded. For example, the computer system 40could maintain a database of the particular types of devices used bydifferent users. Because data from hand held devices may not correspondto a vehicle moving along a road, the computer system 40 may reject datafrom the class of hand held computing devices. Thus the system coulddistinguish between different classes of users and/or user stations 52to determine whether to accept traffic data from that user station.

In another embodiment, the present inventors came to the realizationthat merely encoding the image with a representation of the traffic flowrelative to a single fixed value is not optimal. An example of suchcoding would be red is 0-30 mph, yellow is 3040 mph, and green is 40+mph. This coding is adequate for freeways but when roads are encodedthat have lower speed limits, the encoding should be relative to whatthe speed limit is so that the user knows the relative speed of trafficon the road. Thus coding may correspond to relative speed rather thanabsolute speed. For example, a freeway with speed limit 55 mph would becoded 0-30 mph red, 30-40 mph yellow and 40+ mph green, while a sideroad with a 35 mph speed limit would be coded 0-20 mph red, 20-25 mphyellow and 25+ mph green. This permits relative encoding which is easierto interpret. Alternatively, encoding may be based on other relativemeasures, such as for example, anticipated traffic flow for thatparticular road, section of road, time of day, and statistical historymeasure of traffic in the past. When multiple freeways in the area areall busy, such as Seattle, coding for absolute values may showeverything as red. However, if relative coding is used, the traffic flowmay be relative to other roads so that the encoding dynamically adjuststo encode one road relative to one or more other roads. In this manner,for example, the “fast” road may be green and the “slow” road may bered.

While the present invention has been described in the context ofproviding traffic information, the present invention may also be used toprovide location specific information to mobile users. In one suchembodiment, an information database may be created for weather reports,in which various weather reports are associated with respectivegeographic locations. A user in a vehicle 60 may request a weatherreport from the mobile user station 52. The request would include theuser's geographic location as determined by the GPS receiver 62. Inresponse to the request, the computer system would access the weatherdatabase and select the weather report associated with that geographiclocation. The location specific weather report would then be transmittedto the mobile user station 52. The weather report would then bedisplayed or otherwise communicated to the user through speakers. Othersimilar information databases could likewise be prepared to associateparticular information with geographic locations. In this manner, a userat a mobile user station 52 may easily obtain highly relevantinformation that is specific to the location of the user. In preferredembodiments of the system, the user may receive both traffic informationand other location specific information at the same time, in sequence,or as requested by the user. In one such embodiment, the user maypreselect the information to be retrieved and the sequence of display orcommunication.

The terms and expressions which have been employed in the foregoingspecification are used therein as terms of description and not oflimitation, and there is no intention, in the use of such terms andexpressions, of excluding equivalents of the features shown anddescribed or portions thereof, it being recognized that the scope of theinvention is defined and limited only by the claims which follow.

1. A navigation system comprising: (a) a processor; (b) a memory; (c) aclock; (d) a power supply; (e) a speaker; (f) a graphical display; (g) aroad displayed on said graphical display; (h) said road including adashed center line; (i) a plurality of icons, each representative of acar, graphically displayed on said road.